KR102196528B1 - Electric belt - Google Patents

Abstract

The present invention is a vulcanized product of a rubber composition comprising a rubber component containing an ethylene-α-olefin elastomer, a filler containing silica, a vulcanizing agent containing a sulfur-based vulcanizing agent, and a curable resin containing an amino resin It relates to a transmission belt provided with a rubber layer formed of and a fiber member in contact with the rubber layer.

Description

Electric belt

The present invention relates to a transmission belt, such as a toothed belt, in which a raceway (interlocking raceway) is covered with a fibrous material (gear cloth).

Fiber-reinforced materials made of rubber and fibers are used in industrial products such as tires, belts, hoses, and rubber information. Among these industrial products, ethylene-?-olefin elastomers such as ethylene-propylene-diene copolymer rubber (EPDM) are known as rubbers commonly used in transmission belts. The ethylene-?-olefin elastomer does not have an unsaturated bond in the main chain and is non-polar, so it has excellent heat resistance and cold resistance, while adhesion with fibers is very difficult. For example, a rubber toothed belt based on EPDM does not have sufficient adhesion between EPDM and a cover cloth or a core wire, especially when driving at high temperatures. Since the rubber or the cover fabric in the part is repeatedly deformed with thermal deterioration, peeling occurs between the rubber and the core wire, resulting in jagged teeth, or peeling at the interface between the cover fabric and the rubber. There is a problem that the durability of the belt is greatly reduced.

As a method of improving the adhesion between the rubber and the core wire under high temperature with respect to the transmission belt of which the rubber component is EPDM, in Patent Document 1, the core wire is embedded in an adhesive rubber layer along the belt length direction, and adjacent to the adhesive rubber layer. In a power transmission belt in which a compression rubber layer is arranged on the raceway side and an elongation rubber layer is arranged on the back side, the adhesive rubber layer contains 20 to 70 parts by mass of silica per 100 parts by mass of the rubber component containing ethylene-α-olefin elastomer. A power transmission belt composed of a crosslinked organic peroxide of a compounded rubber composition is disclosed. In this document, since the adhesion between the core wire and the belt body can be maintained at a high level even at high temperatures, the adhesive rubber layer further contains a resorcinic formalin resin (resorcinol resin) or a melamine polymer. It is stated that it is preferable. Further, as the power transmission belt, a V ribbed belt or a cogged V belt is described.

As in this document, in friction transmission belts such as a V-ribbed belt and a cogged V-belt, rubbers of different formulations are often laminated in an adhesive rubber layer and a compressed rubber layer. For this reason, it is advantageous to mix a large amount of carbon black in order to increase mechanical properties such as abrasion resistance and modulus of the rubber, but it may be mentioned that the adhesive strength tends to decrease when the amount of carbon black increases. There, in a friction transmission belt, it is common to arrange rubber of a compound specializing in adhesiveness around the fibrous material, and the belt body is generally formed of rubber of a compound with improved mechanical properties. Also in Patent Document 1, the filler (reinforcing agent) incorporated in the adhesive rubber layer is only silica, and it is considered as a result of avoiding the addition of carbon black that causes a decrease in adhesiveness. Therefore, in the friction transmission belt, the mechanical properties of the adhesive rubber layer itself are not sufficient, and the existence of the adhesive rubber layer also has a structural defect that complicates the belt structure.

On the other hand, in the toothed belt, there are few examples of using the adhesive rubber layer, and the rubber of the belt body is in direct contact with the core wire or the cover fabric. Therefore, in the rubber layer of the toothed belt, in addition to high abrasion resistance and modulus required for power transmission, it is required to have both a core wire and a cover fabric adhesive force. Therefore, as for the rubber layer of the toothed belt, as in Patent Document 1, a blend containing only silica as a filler cannot be employed, and a blend containing carbon black and high adhesion to the fiber member is required.

In Patent Document 2, a transmission belt provided with a rubber portion formed by vulcanizing a rubber composition containing rubber, resorcinol, and a melamine compound is disclosed. As the curing agent (or crosslinking agent) to be blended in the rubber composition, it is described that an organic peroxide type curing agent is preferable, and is also used in Examples. As the rubber, hydrogenated nitrile rubber and EPDM are used in Examples. Further, in the examples, in the rubber composition containing EPDM, 40 parts by mass of silica, 5 parts by mass of carbon black, 1.7 parts by mass or 3.4 parts by mass of a melamine compound are blended with respect to 100 parts by mass of EPDM.

However, in this toothed belt, an organic peroxide is used as a crosslinking agent, but since the organic peroxide attacks the resorcinol resin, which is an adhesive treatment agent for the cover cloth, to deteriorate curing, it becomes difficult to increase the adhesion to the cover cloth. In addition, in a toothed belt, since stress is concentrated in the tooth root portion, it is important to endure the tearing force of the rubber, but since it is crosslinked by organic peroxide, it is not enough to endure the tearing force. Moreover, whether it is because the ratio of the melamine compound to silica is small, the adhesive strength between the rubber part and the core wire is not sufficient, the ratio of carbon black is small, and mechanical properties such as wear resistance and modulus are not sufficient.

Patent Document 1: Japanese Patent Application Laid-Open No. 2008-261489 Patent Document 2: Japanese Patent Laid-Open No. 2013-108564

An object of the present invention is that even when a rubber layer containing an ethylene-α-olefin elastomer and a fiber member in contact with the rubber layer are provided, peeling between the rubber layer and the rubber member is suppressed, and mechanical properties such as abrasion resistance and modulus are provided. It is to provide a transmission belt with high characteristics.

Another object of the present invention is to provide a transmission belt capable of improving durability even when used under high temperature as a toothed belt.

Still another object of the present invention is to provide a transmission belt capable of suppressing peeling even if it is a fiber member formed of either inorganic fiber or organic fiber.

The inventors of the present invention intensively studied in order to achieve the above problems, as a result of the rubber component containing the ethylene-α-olefin elastomer, a filler containing silica, a vulcanizing agent containing a sulfur-based vulcanizing agent, and an amino resin. By combining a curable resin to form the rubber layer of the transmission belt, even if a rubber layer containing an ethylene-α-olefin elastomer and a fiber member in contact with the rubber layer are provided, the rubber layer is separated from the fiber member. It has been found that mechanical properties such as wear resistance and modulus can be improved, and the present invention is completed.

That is, in the transmission belt of the present invention, in the transmission belt having a rubber layer and a fiber member in contact with the rubber layer, the rubber layer comprises a rubber component containing an ethylene-α-olefin elastomer, a filler containing silica, and , A vulcanizing agent containing a sulfur-based vulcanizing agent, and a vulcanizing product of a rubber composition containing a curable resin containing an amino resin. The amino resin may contain a melamine resin. The filler may further contain carbon black. The ratio of the amino resin may be about 10 to 50 parts by mass per 100 parts by mass of silica. The ratio of the silica may be about 10 to 150 parts by mass per 100 parts by mass of carbon black. The rubber layer may contain 5 to 30 parts by mass of silica and 10 to 100 parts by mass of carbon black with respect to 100 parts by mass of the rubber component. The sulfur-based curing agent may be sulfur. The curable resin may not contain a resorcinol resin. The vulcanizing agent may not contain an organic peroxide. The transmission belt of the present invention includes a belt body including a plurality of toothed portions arranged at predetermined intervals along the belt length direction, a back portion in which a core body is embedded, and the plurality of It may be a toothed belt having a cover cloth covering the surface of the toothed portion. The belt body (gear and back) may be the rubber layer. The core body may contain inorganic fibers.

In the present invention, a rubber component containing an ethylene-α-olefin elastomer, a filler containing silica, a vulcanizing agent containing a sulfur-based vulcanizing agent, and a curable resin containing an amino resin are combined to form a rubber layer of a transmission belt. Thus, even if a rubber layer containing an ethylene-α-olefin elastomer and a fiber member in contact with the rubber layer are provided, peeling of the rubber layer and the fiber member can be suppressed, and abrasion resistance, modulus, etc. The mechanical properties of can also be improved. Therefore, durability can be improved even when used as a toothed belt under high temperature. Furthermore, the transmission belt of the present invention can suppress peeling even if it is a fibrous member formed of either of inorganic fibers and organic fibers.

1 is a cross-sectional perspective view showing an example of a transmission belt (gear belt) of the present invention.
2 is a schematic diagram for explaining an endurance running test of a transmission belt in an embodiment.

The transmission belt of the present invention may be provided with a rubber layer and a fiber member in contact with the rubber layer, and may be various friction transmission belts or various meshing transmission belts (gear belts). Among these transmission belts, it may be particularly useful for toothed belts in which a high demand for coexistence with mechanical properties such as abrasion resistance and modulus is high in adhesion between the rubber layer and the fiber member.

1 is a cross-sectional perspective view showing an example of a toothed belt according to the present invention, wherein the toothed belt 1 includes a plurality of toothed portions 2 formed at predetermined intervals along the longitudinal direction of the belt (arrows in the figure), It has a back part 4 in which a plurality of core bodies 3 are embedded along the longitudinal direction of the belt, and a tooth cloth (cover cloth) 5 is attached to the surface of the tooth part 2 (covering). Or laminated). In addition, the toothed portion 2 has a large longitudinal cross-sectional shape ( It is formed in a dai) shape. In the toothed belt 1, the toothed portion 2 and the back portion 4 form a belt body, and this belt body is formed from the rubber layer. Moreover, as a fiber member, the core 3 and the cover cloth 5 correspond.

In addition, the shape of the toothed belt is not limited to the structure shown in Fig. 1, and is formed on at least one side of the belt at a predetermined interval in the longitudinal direction of the belt, and can be engaged with the toothed pulley. It is sufficient to have a plurality of teeth or convex portions. The cross-sectional shape of the toothed portion or the convex portion (the cross-sectional shape in the belt length direction or in the width direction) is not limited to the above-described large-sized shape, and depending on the shape of the toothed pulley, for example, a semicircle, semi-ellipse, polygon (triangle , Square (spherical shape, etc.), etc. may be used. Further, the spacing of the toothed portions or the convex portions adjacent to each other in the lengthwise direction may be, for example, 1 to 10 mm, preferably about 2 to 8 mm, depending on the shape of the toothed pulley.

In the following description, the toothed portions and the convex portions are treated as the same meaning, and each element of the toothed belt having the structure shown in FIG. 1 will be described.

[Tooth (2) and back (4)]

The belt body (tooth part 2 and back part 4) is formed of a vulcanized product of a rubber composition, and the rubber composition includes a rubber component, a filler, a vulcanizing agent, a curable resin (with additives contained as necessary). It includes.

(Rubber component)

The rubber component includes an ethylene-α-olefin elastomer. Examples of the ethylene-α-olefin elastomer include ethylene-α-olefin copolymer rubber, ethylene-α-olefin-diene terpolymer rubber, and the like. Examples of α- olefins, for example, propylene, butene, pentene, methyl pentene, hexene, octene, etc. of the chain (鎖狀) _α-3- C ₁₂ olefins can be exemplified. Of these α- olefin, the _α-3- C ₄ olefins (especially propylene), propylene is preferred. As the diene monomer, usually, a non-conjugated diene monomer such as dicyclopentadiene, methylene norbornene, ethylidene norbornene, 1,4-hexadiene, cyclooctadiene, etc. will be exemplified. I can. Among these diene monomers, ethylidene norbornene and 1,4-hexadiene (especially ethylidene norbornene) are preferable.

Representative ethylene-α-olefin elastomers include, for example, ethylene-propylene copolymer (EPM), ethylene-propylene-diene terpolymer (EPDM, etc.), ethylene-butene copolymer (EBM), ethylene-octene co-mixture ( EOM), etc. may be listed. These ethylene-?-olefin elastomers can be used alone or in combination of two or more.

Because of the, which it is excellent in heat resistance and cold resistance thereof, ethylene -α- olefin-diene terpolymer rubber - is (in particular, such as EPDM ethylene _-α-3- C ₄ olefin-diene terpolymer rubber) are preferable.

In addition to the ethylene-α-olefin elastomer, other rubber components, such as diene rubber (natural rubber, isoprene rubber, butadiene rubber, chloroprene rubber, styrene butadiene), in addition to the ethylene-α-olefin elastomer, as long as the rubber component does not impair the effects of the present invention. Rubber (SBR), vinylpyridine-styrene-butadiene copolymer rubber, acrylonitrile butadiene rubber (nitrile rubber); Hydrogenated products of the diene-based rubbers, such as hydride nitrile rubber (including mixed polymer of hydride nitrile rubber and unsaturated carboxylic acid metal salt), olefin-based rubber (polyoctenylene rubber, ethylene-acetic acid Vinyl copolymer rubber, chlorosulfonated polyethylene rubber, alkylated chlorosulfonated polyethylene rubber, etc.), epichlorohydrin rubber, acrylic rubber, silicone rubber, urethane rubber, fluorine rubber, etc. may be included.

The proportion of the ethylene-α-olefin elastomer is preferably 50% by mass or more with respect to the entire rubber component, preferably 80% by mass or more, more preferably 90% by mass or more (especially 95% by mass or more), and 100% by mass (The rubber component is formed only from an ethylene-α-olefin elastomer). If the proportion of the ethylene-?-olefin elastomer is too small, there is a concern that the heat resistance and cold resistance of the transmission belt are deteriorated.

(filler)

In the present invention, since the mechanical properties of the transmission belt are improved and durability is improved, the filler contains silica. Silica is a fine bulky white powder formed of silicic acid and/or silicate, and because a plurality of silanol groups exist on its surface, it can chemically adhere to a rubber component.

Silica includes dry silica, wet silica, and surface-treated silica. Further, silica can be classified into, for example, dry method white carbon, wet method white carbon, colloidal silica, and precipitated silica by classification in the manufacturing method. These silicas can be used alone or in combination of two or more. Among these, since there are many surface silanol groups and the chemical bonding strength with the rubber component is strong, wet method white carbon containing hydrous silicic acid as a main component is preferable.

The average particle diameter of silica is, for example, about 1 to 1000 nm, preferably 3 to 300 nm, more preferably 5 to 100 nm (especially 10 to 50 nm). If the particle size of the silica is too large, there is a fear that the mechanical properties of the rubber layer (belt body) are deteriorated, and if it is too small, there is a fear that it becomes difficult to uniformly disperse.

Further, silica may be non-porous or porous, but the specific surface area for nitrogen adsorption by the BET method is, for example, 50 to 400 m 2 /g, preferably 70 to 350 m 2 /g, more preferably 100 It may be about 300㎡/g (especially 150-250㎡/g). If the specific surface area is too large, there is a fear that it becomes difficult to uniformly disperse, and if the specific surface area is too small, there is a concern that the mechanical properties of the rubber layer are deteriorated.

The ratio of silica can be selected from a range of about 1 to 100 parts by mass (for example, 5 to 30 parts by mass) per 100 parts by mass of the rubber component, for example, 3 to 50 parts by mass (for example, 5 to 50 parts by mass). Parts by mass), preferably 5 to 40 parts by mass (for example, 10 to 40 parts by mass), more preferably about 8 to 20 parts by mass (especially 10 to 15 parts by mass). In addition, the ratio of silica can be selected from a range of about 1 to 300 parts by mass with respect to 100 parts by mass of carbon black described later, for example, 5 to 200 parts by mass (eg 10 to 150 parts by mass), preferably Is about 10 to 100 parts by mass (for example, 12 to 50 parts by mass), more preferably about 13 to 30 parts by mass (particularly 15 to 20 parts by mass). If the ratio of silica is too small, there is a concern that adhesion or reinforcing properties may be deteriorated, and if it is too large, it becomes difficult to uniformly disperse in the rubber layer, and there is a fear that the adhesion with the fibrous member (especially cover fabric) decreases. .

In the present invention, it is preferable to further contain carbon black in addition to silica as a filler. Carbon black has the effect of remarkably improving the fatigue rupture resistance and abrasion resistance of the rubber layer, and by combining silica and carbon black, mechanical properties such as modulus and adhesion to the fiber member can be achieved. The durability of the belt can be improved.

The average particle diameter of the carbon black is, for example, 5 to 200 nm, preferably 10 to 150 nm, more preferably about 15 to 100 nm, and because of the high reinforcing effect, a small particle diameter carbon black may be used, and the average particle diameter is , For example, 5 to 38 nm, preferably 10 to 35 nm, more preferably about 15 to 30 nm may be used. As a carbon black having a small particle diameter, SAF, ISAF-HM, ISAF-LM, HAF-LS, HAF, HAF-HS, etc. can be illustrated, for example. These carbon blacks can be used alone or in combination.

The ratio of carbon black can be selected from a range of about 10 to 150 parts by mass (for example, 10 to 100 parts by mass) per 100 parts by mass of the rubber component, for example, 20 to 120 parts by mass, preferably 30 to It is about 100 parts by mass (for example, 35 to 80 parts by mass), more preferably 40 to 70 parts by mass (particularly 50 to 60 parts by mass). If the proportion of carbon black is too small, there is a fear that reinforcing properties and abrasion resistance cannot be sufficiently exhibited, and if too large, there is a concern that adhesiveness decreases or it becomes difficult to uniformly disperse.

The filler may further contain a common filler. As a common filler, clay, calcium carbonate, talc, mica, etc. can be mentioned, for example. These common fillers can be used alone or in combination of two or more.

The total ratio of silica and carbon black (in the case of silica only, the ratio of silica) may be 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more (especially 80% by mass) based on the entire filler. % Or more) may be sufficient, and 90 mass% or more (especially 100 mass%) may be sufficient. If the ratio of silica and carbon black is too small, there is a concern that the mechanical properties of the rubber layer are deteriorated.

The ratio (total ratio) of the filler is, for example, 30 to 100 parts by mass, preferably 50 to 90 parts by mass, and more preferably about 60 to 80 parts by mass per 100 parts by mass of the rubber component. If the ratio of the filler is too small, there is a concern that mechanical properties such as abrasion resistance and modulus are deteriorated, and if too large, there is a concern that the adhesiveness to the fibrous member decreases.

(Curing agent)

The vulcanizing agent (or crosslinking agent) contains a sulfur-based vulcanizing agent because the adhesiveness to the fiber member (especially a core body containing inorganic fibers) can be improved. Examples of the sulfur-based vulcanizing agent include powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, highly dispersible sulfur, and chlorinated sulfur (sulfur monochloride, sulfur dichloride, etc.). These sulfur-based vulcanizing agents can be used alone or in combination of two or more. Among these sulfur-based vulcanizing agents, sulfur such as powdered sulfur is preferable.

The vulcanizing agent may further contain other vulcanizing agents as long as the effect of the present invention is not impaired. As another vulcanizing agent, an organic peroxide (diacyl peroxide, peroxy ester, dialkyl peroxide, etc.) etc. can be mentioned, for example.

The proportion of the sulfur-based vulcanizing agent (especially sulfur) is preferably 50% by mass or more, more preferably 80% by mass or more, further preferably 90% by mass or more (especially 95) with respect to the total vulcanizing agent (or crosslinking agent). Mass% or more), and may be 100 mass% (sulfur-based vulcanizing agent alone). If the proportion of the sulfur-based vulcanizing agent is too small, there is a fear that the adhesion to the fiber member (especially the core) decreases. In particular, in the present invention, since the adhesiveness with the fibrous member (especially the core) can be improved, the curing agent preferably does not contain an organic peroxide substantially, and preferably does not contain an organic peroxide at all. In the specification and claims of the present invention, ``substantially free of organic peroxides'' means that they are not included except for incorporation as unavoidable impurities, and the upper limit of the content is the vulcanizing agent (or crosslinking agent) as a whole. For example, it is about 0.1% by mass.

The ratio of the vulcanizing agent (especially sulfur-based vulcanizing agent) can be selected from the range of about 0.1 to 20 parts by mass per 100 parts by mass of the rubber component, for example 0.2 to 10 parts by mass, preferably 0.5 to 5 parts by mass. , More preferably, it is about 0.5 to 3 parts by mass (especially 0.8 to 2 parts by mass). If the proportion of the vulcanizing agent is too small, there is a concern that mechanical properties such as abrasion resistance of the rubber layer are deteriorated, and if it is too large, there is a concern that the flexibility is lowered.

(Curable resin)

The curable resin (adhesion improving agent or binder resin) contains an amino resin because it can improve the adhesiveness with the fiber member.

As the amino resin, conventional amino resins such as melamine resin, urea resin (urea resin), guanamine resin, aniline resin, and the like can be mentioned. These amino resins can be used alone or in combination of two or more. Among these amino resins, melamine resins are preferred because adhesion to a fiber member (especially a core body including inorganic fibers under high temperature) can be improved.

The melamine resin may be a conventional melamine resin, and may be a reaction product (e.g., an initial condensate or a prepolymer) obtained by reacting melamine and formaldehyde under neutral or alkaline conditions. Moreover, as long as the effects of the present invention are not impaired, compounds having other amino groups, such as urea, guanamine (formoguanamine, acetguanamine, benzoguanamine, etc.), aniline, and the like are used in combination with melamine. You may do it. The ratio of the compound having another amino group may be 0.3 mol or less (particularly 0.1 mol or less) per 1 mol of melamine.

As the formaldehyde, a condensate of formaldehyde (for example, trioxane, paraformaldehyde, etc.) may be used, or an aqueous solution of formaldehyde (formalin, etc.) may be used.

The ratio (use ratio) of melamine and formaldehyde is, for example, the former/the latter (molar ratio) = 1/1 to 1/10, preferably 1/3 to 1/8, more preferably 1/5 to It may be about 1/7.

As the melamine resin, for example, mono to hexamethylol melamine such as trimethylol melamine and hexamethylol melamine are generally used, and because of heat resistance and adhesiveness, tetra to hexamethylol melamine (especially hexamethylol melamine ) And the like are preferable. Melamine resin (in particular, tetra to hexa-methylol melamine) are screen ether, an alkyl group (for example, C _{1- 4} alkyl group such as methyl, ethyl, n- butyl, isobutyl) Therefore, the viewpoint of handleability You may have it. Examples of alkyl ether etherified melamine resin, for example, mono- to hexa C _{1- 4} alkoxy, and the universal methyl melamine or the like, hexamethoxymethylmelamine, hexamethylene -n- portion such as methoxymethyl melamine, hexa-isobutoxy-methyl melamine hexahydro C _{1- 4} are alkoxymethyl melamine is preferably used.

The proportion of the melamine resin is preferably 50% by mass or more, more preferably 80% by mass or more, still more preferably 90% by mass or more (especially 95% by mass or more) based on the total amino resin, and 100% by mass (melamine Resin alone) may be used.

The proportion of amino resin (especially melamine resin) can be selected from a range of about 1 to 100 parts by mass per 100 parts by mass of silica, for example 5 to 80 parts by mass, preferably 8 to 60 parts by mass, more preferably It is about 10 to 50 parts by mass (especially 20 to 50 parts by mass). If the proportion of the amino resin is too small, there is a concern that the adhesion to the fibrous member (especially the core) decreases, and if too large, there is a fear that the adhesion to the fibrous member and the bending fatigue resistance are reduced.

The curable resin may further contain other curable resins (resorcinol resin, etc.) as long as the effect of the present invention is not impaired. The resorcinol resin (resorcinformalin) may be a cocondensation product of phenols containing resorcinol and formaldehyde, or may be a mixture of latex.

The proportion of the amino resin (particularly melamine resin) is preferably 50% by mass or more, more preferably 80% by mass or more, and still more preferably 90% by mass or more (especially 95% by mass or more) with respect to the entire curable resin, It may be 100% by mass (melamine resin alone). If the proportion of the amino resin is too small, there is a concern that heat resistance and adhesion to the fibrous member (especially the core) may decrease. In particular, in the present invention, since the adhesiveness with the fiber member (especially the core) can be improved, the curable resin preferably does not contain a resorcinol resin substantially, and does not contain a resorcinol resin at all. It is particularly preferred. In the specification and claims of the present invention, "substantially free of resorcinol resin" means that it is not included except for incorporation as an inevitable impurity, and the upper limit of its content is with respect to the entire curable resin. For example, it is about 0.1% by mass.

The ratio of curable resin (especially amino resin) can be selected from the range of about 0.1 to 30 parts by mass per 100 parts by mass of the rubber component, for example, 0.3 to 20 parts by mass, preferably 0.5 to It is about 10 parts by mass, more preferably 1 to 8 parts by mass (especially 2 to 5 parts by mass).

(Other additives)

The belt body (the rubber composition forming the teeth 2 and the back 4) may contain various commonly used additives (or blending agents) as necessary.

Examples of additives include vulcanization aids (areenbismaleimide such as N,N'-m-phenylenedimaleimide or aromatic bismaleimide), vulcanization accelerators (tetramethylthiuram monosulfide (TMTM)), Tetramethylthiuram disulfide (TMTD), tetraethylthiuram disulfide (TETD), tetrabutylthiuram disulfide (TBTD), dipentamethylenethiuram tetrasulfide (DPTT), N,N'- Thiuram-based accelerators such as dimethyl-N,N'-diphenylthiuram disulfide; 2-mercaptobenzothiazole, 2-mercaptobenzothiazole zinc salt, 2-mercaptothiazoline, dibenzothiazyl disulfide, 2-(4'-morpholinodithio)benzothiazole, etc. Sol accelerator; Sulfenamide accelerators such as N-cyclohexyl-2-benzothiazylsulfenamide (CBS) and N,N'-dicyclohexyl-2-benzothiazylsulfenamide; Guanidines such as diphenylguanidine and di-o-trylguanidine; Area-based or thiourea-based accelerators such as ethylene thiourea; Dithiocarbamate salts; Xanthogen salts, etc.], vulcanization retarders, metal oxides (zinc oxide, magnesium oxide, calcium oxide, barium oxide, iron oxide, copper oxide, titanium oxide, aluminum oxide, etc.), short fibers (cellulose such as cotton or rayon) Short fibers such as fibers, polyester fibers (PET fibers, etc.), polyamide fibers (aliphatic polyamide fibers such as polyamide 6, aramid fibers, etc.), plasticizers, softeners (parlipine oil, naphthenic oil, etc.) Oils, etc.), processing agents or processing aids (stearic acid, stearic acid metal salt, wax, paraffin, etc.), anti-aging agents (aromatic amines, benzimidazole-based anti-aging agents, etc.), coloring agents, tackifiers, coupling agents (silane coupling agents, etc.) ), stabilizers (antioxidants, ultraviolet absorbers, heat stabilizers, etc.), lubricants, flame retardants, antistatic agents, etc. may be exemplified. These additives can be used alone or in combination of two or more.

The total proportion of the additives is, for example, 1 to 100 parts by mass, preferably 5 to 50 parts by mass, and more preferably about 10 to 20 parts by mass per 100 parts by mass of the rubber component. Specifically, for 100 parts by mass of the rubber component, for example, the ratio of the vulcanization accelerator is 0.1 to 10 parts by mass (especially 0.5 to 5 parts by mass), and the ratio of the metal oxide is 1 to 20 parts by mass (especially 3 to 10 parts by mass). Parts), the ratio of the softener is 1 to 20 parts by mass (especially 3 to 10 parts by mass), the ratio of the processing (crude) agent is 0.1 to 5 parts by mass (especially 0.5 to 3 parts by mass), the ratio of the anti-aging agent is 1 to It is about 20 parts by mass (especially 3 to 10 parts by mass).

Further, the rubber composition forming the toothed portion 2 and the back portion 4 may be a different rubber composition or the same rubber composition, as long as the adhesion between the toothed portion 2 and the back portion 4 is not impaired. Usually, the toothed portion 2 and the back portion 4 are of the same type of rubber (e.g., ethylene-α-olefin elastomer, and other types of rubber, etc.) or the same type of rubber component (e.g., The same kind of ethylene-?-olefin elastomer, etc.) are often included.

[Core (3)]

The core 3 is embedded in the belt body along the longitudinal direction of the belt in order to improve the stability of running and the belt strength, and generally, a plurality of core wires (braided cords) extending along the longitudinal direction of the belt It is buried in the body.

The core wire may be formed of a braided cord by combining a plurality of strands or multifilament yarns. Of these, a braided cord of strands is preferable, and one strand may be formed by bundling filaments (long fibers). The average wire diameter of the core wire (the fiber diameter of the braided cord) is, for example, about 0.2 to 0.6 mm. The thickness of the filaments forming the braided cord, the number of converging filaments, the number of strands, and the strand configuration of the braiding method are not particularly limited.

The fibers forming the core wire are not particularly limited, and examples include polyester fibers (polyalkylene arylate fibers, polyparaphenylene naphthalate fibers), polybenzoxazole fibers, acrylic fibers, and polyamide fibers. Inorganic fibers such as fiber-containing fibers (aliphatic polyamide fibers, aramid fibers, etc.), glass fibers, carbon fibers, and metal fibers (steel fibers) may be exemplified. These fibers may be used alone or in combination of two or more. As the fibers forming the core wire, since they have low elongation and high strength, for example, synthetic fibers such as polyester fibers and polyamide fibers, inorganic fibers such as glass fibers and carbon fibers are generally used. The composition of the glass fiber is not particularly limited, and E glass, S glass (high strength glass), C glass, or the like may be used. Among these, high strength glass fibers and carbon fibers are preferred because of their high strength and low elongation, and high strength glass fibers are particularly preferred from the viewpoint of economy.

A plurality of core wires may be embedded at predetermined intervals (or pitches) (or at equal intervals) in the width direction of the belt. The spacing (spinning pitch) between adjacent core wires may be, for example, 0.5 to 2 mm, preferably about 0.8 to 1.5 mm, depending on the diameter of the core wire.

The core wire may be subjected to adhesion treatment in order to increase the adhesion to the belt body. As a method of bonding treatment, for example, a braided cord may be immersed in a resolsin-formalin-latex treatment liquid (RFL treatment liquid), followed by heating and drying to form a uniform adhesive layer on the surface of the braided cord. The RFL treatment liquid is a mixture obtained by mixing an initial condensation product of resolsin and formalin in latex, and the latex is, for example, chloroprene rubber, styrene-butadiene-vinylpyridine terpolymer (VP latex), nitrile rubber, hydrogenation. Nitrile rubber or the like may be used. Further, as a method of adhesion treatment, after pretreatment with an epoxy compound or an isocyanate compound is performed, a method of treating with an RFL treatment liquid may be used.

[Cover fore (5)]

A cover fabric 5 is coated or laminated on the toothed portion 2 of the toothed belt 1 as a pulley contact surface, and the cover fabric 5 is integrated with the toothed portion 2.

The cover fabric is preferably a woven fabric. The woven structure (woven structure) of the cover fabric is not particularly limited, and may be a woven fabric woven by regularly interlacing warp and weft yarns vertically and horizontally. For example, twill weave (serpentine weave) or woven fabric ( Fabrics such as suja, satin, plain weave, etc. may be used. Among these, twill weave and main weave structure are preferable because there are few contact points of fibers (or yarns) and the treatment liquid is easily impregnated.

The shape of the warp and weft is not particularly limited, and the filaments (long fibers) are pulled and aligned, multifilament yarns that are braided, monofilament yarns that are one long fiber, span yarns that are short fibers are combined (絲) ( Spun yarn) may be used. When the warp or weft yarns are multifilament yarns or spanned yarns, kneaded yarns or blended yarns using a plurality of types of fibers may be used. Among them, it is preferable that the weft yarn contains an elastic yarn having elasticity. As the elastic yarn, for example, an elastic yarn in which the material itself has elasticity, such as spandex made of polyurethane, or a processed yarn obtained by stretching fibers (for example, woolly processing, crimping processing, etc.) may be used. . On the other hand, because of the point of weaving, elastic yarn is not usually used for warp. Moreover, as the cover fabric, since the stretchability of the cover fabric in the belt length direction can be ensured, it is preferable to arrange the warp of the woven fabric to extend in the belt width direction and the weft yarn to extend in the belt length direction.

The average diameter of the fibers (or yarns) constituting the cover fabric may be, for example, 5 to 100 µm, preferably about 10 to 50 µm. In addition, the average fiber diameter (thickness) of the yarn formed of fibers may be, for example, 100 to 1000 dtex, preferably 300 to 700 dtex for weft, and 50 to 500 dtex for warp, preferably 100 to It may be about 300 dtex. The density (bone/cm) of the weft may be, for example, 5 to 50, preferably about 10 to 30, and the density of the warp yarn (bone/cm) is, for example, 10 to 300, preferably 20 to 100 It may be about.

Examples of the fibers forming the weft and warp of the cover fabric include cellulose yarn fibers (cellulose fibers (cellulose fibers derived from plants such as cotton, animals, or bacteria), regenerated cellulose fibers such as rayon, cellulose ester fibers, etc.), Polyolefin fiber, vinyl alcohol fiber, polyamide fiber (aliphatic polyamide fiber such as polyamide 6 fiber, polyamide 66 fiber, polyamide 46 fiber, aromatic polyamide fiber such as aramid fiber), polyester fiber (example) for example, polyethylene terephthalate (PET) fibers, polypropylene terephthalate (PPT) fiber, polytrimethylene terephthalate (PTT) fiber, a polyethylene naphthalate (PEN) fiber, such as the _2- C ₄ alkylene-C _{6 - 14} aryl Rate-based fibers; Polyarylate fibers, fully aromatic polyester fibers such as liquid crystal polyester fibers, etc.], polyphenylene ether fibers, polyether ether ketone fibers, polyether sulfone fibers, polybenzoxazole fibers (polyparaphenyl Renbenzobisoxazole (PBO) fibers, etc.), polyurethane fibers, inorganic fibers such as carbon fibers, etc. may be exemplified. These fibers can be used singly or in combination of two or more.

Among these fibers, organic fibers are generally used, and cellulose fibers such as cotton and rayon, polyester fibers (PET fibers, etc.), polyamide fibers (aliphatic polyamide fibers such as polyamide 66 fibers, aramid fibers, etc.), Polybenzoxazole-based fibers and the like are preferred.

The thickness of the cover fabric is not particularly limited, and may be, for example, about 0.3 to 1.5 mm, preferably about 0.5 to 1.2 mm.

In order to increase the adhesion between the belt body (gear portion 2 and back portion 4) and the cover cloth, an adhesive treatment may be applied to the cover cloth. As a method of adhesion treatment, for example, a woven fabric may be immersed in a resolsin-formalin-latex treatment liquid (RFL treatment liquid), followed by heating and drying to form a uniform adhesive layer on the surface of the woven fabric. Moreover, the method of adhesion treatment may be a method of pretreating with an epoxy compound or an isocyanate compound, followed by treatment with an RFL treatment solution, and dissolving the rubber composition in an organic solvent such as methyl ethyl ketone, toluene, and xylene,糊), the woven fabric is immersed in the rubber paste, and the rubber composition is impregnated and adhered. These methods can be used alone or in combination, and the order of treatment and the number of treatments are not limited.

[Method of manufacturing electric belt]

The transmission belt of the present invention can be manufactured by a conventional method, and for example, the toothed belt 1 shown in Fig. 1 can be manufactured by the following method. First, the canvas forming the cover fabric 5 is wound and attached to a cylindrical mold having a plurality of grooves corresponding to the toothed portions 2 of the toothed belt 1. Subsequently, the cord constituting the core 3 is spirally wound onto a cylindrical mold on which the canvas is wound and pasted at a predetermined pitch (a predetermined pitch with respect to the axial direction of the cylindrical mold). Next, the unvulcanized rubber sheet forming the back portion 4 and the tooth portion 2 is wound and pasted to form an unvulcanized sleeve (unvulcanized laminate). Further, the cylindrical mold wound with the unvulcanized sleeve is transferred into a vulcanizing tube and heated and pressurized to press-fit the rubber sheet into the mold groove to form the teeth 2 together with the vulcanization. Finally, the individual toothed belt 1 can be manufactured by cutting the obtained sleeve-shaped molded article with a cutting knife according to a predetermined cut width.

In addition, the toothed belt 1 may be produced by the following procedure by the preforming method. First, the cover fabric 5 and the toothed portion 2 are preformed with a toothed mold to obtain a preform. Next, the obtained green body is wound around a mold, and the core 3 is spirally spun for that purpose. After the unvulcanized rubber constituting the back part 4 is wound and pasted thereon, the whole is vulcanized in a vulcanizing tube, and a toothed belt 1 is obtained. In this preforming method, since the cover cloth 5 and the toothed portion 2 are preformed before curing, the unvulcanized rubber constituting the back portion 4 at the time of curing is removed from the inside (abdominal side) between the core body 3 and That is, it is not necessary to form the toothed portion 2 by elongating the cover cloth 5 by flowing to the toothed portion 2 side). Therefore, it becomes possible to narrow the distance (pitch) between core wires.

Example

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited by these examples. In the following examples, the raw materials used in the examples and the measurement method or evaluation method in each physical property are shown below. In addition, unless specifically stated otherwise, "parts" and "%" are based on mass.

[Raw material]

EPDM: "EPT4021" manufactured by Sanji Chemical Co., Ltd., ethylene content 51% by mass, diene content 8.1% by mass

Carbon Black: "Cist V" manufactured by Tokai Carbon Co., Ltd.

Silica: Evonik, Degusa, Japan Co., Ltd. "Ultrazil VN3", BET specific surface area 175㎡/g

Softener (paraffin oil): "Diana Process Oil PW90" manufactured by Ipo-Koyang Co., Ltd.

Anti-aging agent: 「Non-Flex OD3」 made by SEIKO Chemical Co., Ltd.

Zinc Oxide: 「Zinc Oxide 2 Types」 manufactured by Hwahwaguk Industrial Co., Ltd.

Stearic acid: "Stearic acid Tsubaki" made by Nippon

Hexamethoxymethylmelamine (HMMM): 「PP-1890S」 by Power Plast

Benzoguanamine: manufactured by Japan Co., Ltd.

Resorcinol resin: "Phenacolite Resin (B-18-S)" manufactured by INDSPEC Chemical Corporation

Curing accelerator A: "Sancera-TT" manufactured by Sanshin Chemical Industry Co., Ltd.

Curing accelerator B: 「Noxera-CZ」 made by Daesik Shin-Hwaguk Industrial Co., Ltd.

Curing accelerator C: 「Noxera-DM-P」 made by Daesung Shin-Hwaguk Industrial Co., Ltd.

Sulfur: Made by U.S.

Organic peroxide: "P-40MB(K)" manufactured by Japan Corporation

Glass core wire: K glass with composition 3/0 (filament diameter 6㎛)

Canvas (reinforcement canvas): Composition 2/2 twill polyamide canvas (thickness 0.70mm)

[Hardness and 50% tensile stress]

The properties of the crosslinked rubber obtained by press crosslinking the rubber composition shown in Table 1 at 165°C for 30 minutes were evaluated. The hardness (JIS-A) of the obtained crosslinked rubber was measured according to JIS K6253 (2012), and the tensile stress M50 at 50% elongation was measured according to JIS K6251 (2010).

[Core wire peeling force]

On the unvulcanized rubber sheet (thickness 4 mm) formed of the rubber composition shown in Table 1, a plurality of glass core wires were arranged in parallel so that the width was 25 mm (fiber spacing 0.1 mm), and a pressure of 2.0 MPa was applied with a press plate. It was added and vulcanized at 160°C for 30 minutes to prepare a rectangular sample (25 mm in width × 150 mm in length × 4 mm in thickness) for a peel test. Then, in accordance with JIS K6256 (2013), a peel test was performed at a tensile speed of 50 mm/min, and the adhesive force (vulcanized adhesive force) between the core wire and the adhesive rubber was measured.

[Canvas Peeling Force]

An unvulcanized rubber sheet (15 cm long, 3 cm wide, 4 mm thick) formed from the rubber composition shown in Table 1 and a canvas (15 cm long, 3 cm wide) were stacked, and a canvas for reinforcement was placed on the opposite side by inserting the canvas and the unvulcanized rubber sheet. It was placed and cured in this state. Curing conditions were made into 165 degreeC x 30 minutes. At this time, before lamination, the space between the canvas and the unvulcanized rubber sheet was separated by using a marking tape in a portion of only 2.5 cm in the longitudinal direction. After vulcanization, the end separated by the masking tape (the end of the canvas, the end of the rubber sheet with reinforcing canvas) was pinched by the upper and lower chaks of the autograph, and the pulling speed was set at 50 mm/min. The maximum value of the peeling force (N/25mm) at this time was taken as the canvas peeling force.

[Belt running durability]

After the canvas was wound and pasted on a toothed attachment mold for belt production, the glass core wire subjected to the bonding treatment was spirally wound with a predetermined tension at a predetermined pitch. On this core wire, an unvulcanized rubber sheet formed of the rubber composition shown in Table 1 is pasted, put into a vulcanizing tube, and vulcanized under pressure at 165°C for 30 minutes by a conventional press-fitting method, and the back surface of the belt is polished to a certain thickness and It was cut in width to obtain a toothed belt. The design of this toothed belt was tooth type: S2M, tooth pitch: 2 mm, tooth number: 170, and belt width: 25 mm. With respect to the obtained toothed belt, a running test was conducted at an atmosphere temperature of 100°C according to the layout shown in FIG. 2 to evaluate the presence or absence of tooth cracking and canvas peeling. If the core wire peeling force is low, the teeth of the belt are separated from the core wire, and a tooth breakage failure occurs. In addition, the running time was stopped at a maximum of 400 hours.

Examples 1 to 10 and Comparative Examples 1 to 6

A sample was prepared using the rubber composition shown in Table 1, and the results of evaluation of hardness and 50% tensile stress, core wire peeling force, canvas peeling force, and belt running durability are shown in Table 1.

From the results of Table 1, it can be determined that the transmission belts of Examples 1 to 10 achieve a running time of 300 hours or more and have sufficient durability in practical use.

In addition, in Example 6, although the mass ratio of the melamine resin to silica was 5% by mass, it was a condition where the mass ratio of the melamine resin was as low as 5%.

In Example 7, the mass ratio of the melamine resin to the silica was 60% by mass, which was a high condition, but it became a jagged breakage in 300 hours.

In addition, in Example 8, the blending amount of silica was as high as 50 parts by mass and the amount of carbon black was as low as 20 parts by mass, and a cover cloth peeling failure occurred in 300 hours.

In addition, Example 9 was a condition in which a resorcinol resin was added, and it became a jagged breakdown in 300 hours. On the other hand, in Example 2 in which the resorcinol resin was not added, it was judged that the addition of the resorcinol resin did not contribute to the improvement of durability because the belt was running for 400 hours without any failure. have.

In addition, Example 10 was a condition in which a guanamine resin was included as an amino resin, and compared with Comparative Example 1, an increase in hardness and tensile stress was observed. The core-wire peeling force and the canvas peeling force were also increased as in the case of containing the melamine resin, but the peeling force at 100°C became a slightly lower tendency. That is, the durability under high temperature was slightly superior to the melamine resin than the guanamine resin.

From the above results, Examples 1 to 5 can be judged to have particularly excellent durability, without showing any breakage of teeth or peeling of the cover fabric even after running for 400 hours.

On the other hand, in Comparative Examples 1 to 6, tooth chamfering occurred in less than 300 hours of running, and sufficient durability was not shown.

Specifically, Comparative Examples 1 to 3 were conditions in which melamine resin and/or silica were not added, but it became a jagged breakdown in running 200 to 250 hours.

Comparative Examples 4 and 6 were conditions in which crosslinking was performed with an organic peroxide, but it became a jagged breakage in 10 hours running.

Moreover, in Comparative Example 5, although the melamine resin was not added but the resorcinol resin was added, it became a jagged breakdown in 200 hours of running.

Although the present invention has been described in detail and with reference to specific embodiments, it is clear to those skilled in the art that various modifications and changes can be added without departing from the spirit and scope of the present invention.

This application is based on Japanese Patent Application No. 2016-102618 filed on May 23, 2016 and Japanese Patent Application No. 2017-096586 on May 15, 2017, the contents of which are incorporated herein by reference.

The transmission belt of the present invention can be used for various transmission belts (friction transmission belts, mesh transmission belts, etc.) provided with a fiber member in contact with a rubber layer, and in particular, it can be effectively used for mesh transmission belts (gear belts). . In addition, the toothed transmission belt is combined with a toothed pulley, in various fields requiring synchronization between input and output, for example, power transmission of engines such as automobiles and motorcycles, power transmission of motors, pumps, etc., automatic doors. , It can be used for machinery such as automated machines, photocopiers and printing machines In particular, it can be used as peripheral equipment (peripheral parts) such as a power transmission belt (timing belt or cogged belt) of an automobile engine.

1. Toothed belt
2. Toothed part
3. Body
4. Back
5. Cover Cannon (Sawtooth)

Claims (11)

A toothed belt having a belt main body including a plurality of toothed portions arranged at predetermined intervals along the belt length direction and a back portion in which a core body is embedded, and a cover cloth covering the surface of the plurality of toothed portions,
Vulcanization of a rubber composition in which the belt body contains a rubber component containing an ethylene-α-olefin elastomer, a filler containing silica, a vulcanizing agent containing a sulfur-based vulcanizing agent, and a curable resin containing an amino resin It is a rubber layer formed of water,
The toothed belt, wherein the ratio of the amino resin is 10 to 50 parts by mass per 100 parts by mass of silica. The toothed belt according to claim 1, wherein the amino resin comprises melamine resin. The toothed belt of claim 1, wherein the filler further comprises carbon black. delete The toothed belt according to claim 3, wherein the ratio of the silica is 10 to 150 parts by mass per 100 parts by mass of carbon black. The toothed belt according to claim 3, comprising 5 to 30 parts by mass of silica and 10 to 100 parts by mass of carbon black with respect to 100 parts by mass of the rubber component. The toothed belt according to claim 1, wherein the sulfur-based curing agent is sulfur. The toothed belt of claim 1, wherein the curable resin is substantially free of resorcinol resin. The toothed belt of claim 1, wherein the curing agent is substantially free of organic peroxides. delete The toothed belt according to claim 1, wherein the core body contains inorganic fibers.

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